1. Field Of The Invention
The subject invention generally pertains to loading dock shelters, and more specifically to a lower draft pad seal.
2. Description Of Related Art
When an exterior doorway of a building is used for loading and unloading trucks, the doorway may often include a dock shelter to help shield against the weather. The dock shelter seals off gaps that might otherwise exist between the exterior face of the building and the back end of the truck. Dock shelters often have projecting members that protrude outwardly from the face of the building and run generally along the top and lateral sides of the doorway. From a protruding edge of the projecting members, a top extending member and two laterally extending members may extend inward and generally parallel to the building face to help seal against the truck's top and sides, respectively. The laterally extending members are often made of a fabric or flexible foam. The rear bottom edge of the truck is often partially sealed off by a bumper pad or dock leveler. The remaining gaps are two inner bottom corners of the dock shelter at the lower back sides of the truck. These gaps are often partially sealed by draft pads attached to the lower ends of the projecting members.
For example, U.S. Pat. No. 4,885,881 (specifically incorporated by reference herein) discloses a pyramidal foam draft pad that hangs from a single point along an inner corner of a dock shelter. And U.S. Pat. No. 3,792,559 (specifically incorporated by reference herein) discloses a wedge-shaped pad. Both of these pads, however, have a generally full triangular surface that abuts the laterally extending member. This large contact area creates a significant compressive force against which the laterally extending member must deflect whenever a truck enters the dock shelter. Since laterally extending members are notorious for wear at this area of contact, it can be important to minimize the compressive forces here.
In the '559 patent, the draft pad has essentially a full triangular surface that abuts the building as well as the laterally extending member. This aggravates the wear problem at the laterally extending member, because a full contact area at both ends of the pad can increase the overall force required to compress the pad. Moreover, the higher compressive forces can be further transmitted to the projecting member, which thus needs to be reinforced accordingly (note the substantial size of backing member 39 of the '559 patent).
With pyramidal-shaped draft pads, its asymmetry means one may need right-hand and left-hand designs to seal dock shelters whose projecting members protrude farther from the building than its laterally extending member extend inward. Also, it can be desirable to have more sealing contact area between the draft pad and the projecting member than what is provided by a pyramidal design. Moreover, a single point attachment tends to allow pyramidal draft pads to sag more than pads having attachment that is more broadly distributed.